1. Field of the Invention
This invention relates to electrographic systems and, in particular, it relates to apparatus for the transport of developer material containing magnetically attractable particles for the development of latent electrographic images. More particularly, this invention relates to an apparatus having a single transport member for conveying such magnetically attractable particles from a first position to a second position where the developer material can be transported further and utilized to develop the latent image.
2. Description of the Prior Art
Various devices are known for transporting developer material containing magnetically attractable particles from a supply of the developer material to a latent image bearing surface or to some form of applicator for subsequent presentation to a latent image bearing surface. Such devices include the employment of an endless conveyer belt/elevator configuration with buckets for transporting developer material for delivery to an elevated position and subsequent delivery to a latent image bearing surface, e.g., a photosensitive drum. Such configurations are relatively costly and complex and do not lend themselves to compact installations.
U.S. Pat. No. 3,635,553 discloses an improved means for transporting developer material to a remote location. A rotatable frame, having a plurality of scoops mounted thereon, which rotates through a sump of developer material and then to an elevated position is described. Each scoop contains an orifice through which developer can enter from the sump and be discharged at the elevated position to cascade over a photosensitive plate. Such a device has the disadvantages of being relatively complex and of creating an undesirable degree of agitation and subsequent uncontrolled distribution of some of the developer material in unwanted areas of the device especially when operated at high speeds.
U.S. Pat. No. 3,113,042 discloses a means whereby a magnetically attractable developer material is conveyed from a reservoir to a remote location by a stationary conveyor mechanism. A series of sequentially energized electromagnets, extending in a linear array behind a smooth surfaced nonmagnetic member and extending from a remote reservoir to a photoconducive surface, are utilized to transport developer material from the reservoir. While this means does provide for better control of the developer material, it again is relatively costly to produce and does not lend itself to a small and compact design.
U.S. Pat. No. 2,846,333 discloses the use of a plurality of like discs which are spaced apart along a rotatable shaft and are fastened to the shaft at an angle of less than 90 degrees. A magnetic field is presented at the edge of the discs. The shaft and a moving photoconductor are positioned so that photoconductor passes close to the edge of each disc with the discs extending into a hopper containing magnetically attractable developer particles. As the discs are rotated, developer particles are carried at the edge of each disc to the space between the photoconductor and the discs where some of the particles are deposited on the photoconductor. Such apparatus requires a multiplicity of discs with the discs oriented so the edges of the discs are parallel to the surface of the photoconductor. With this arrangement, a substantial amount of space, as well as a large number of discs, is required for the apparatus for movement of the developer material from the hopper to the photoconductor.